The genus Helianthemum Miller, includes 12 annual or perennial species in the Flora of Turkey, 4 of which are endemic. In this study, macro and micromorphological, anatomical and palynological characteristics of the endemic Helianthemum nummularium L. Miller subsp. lycaonicum Coode&Cullen are studied. This species is grown on steppe, chalky and limestone slopes in Turkey. In morphological studies, detailed descriptions of the H. nummularium subsp. lycaonicum and characteristic features are given. Also, identification key of four subspecies added. In anatomical studies, cross sections of root, stem and leaf were examined. Besides, seed morphology is studied by SEM. According that, seeds are ovate. The seed coat ornamentation is verrucate. The pollen grains are tricolporate, medium sized and prolate. Apocolpial area is rather narrow. Exine is very thin. Exine ornamentation is identified as striate-perforate on SEM studies